The present invention relates generally to a vacuum pump and more particularly to a hand-operated vacuum pump.
There are presently available a variety of hand-operated vacuum pumps. Two such pumps are shown in U.S. Pat. No. 3,612,722 and United Kingdom Pat. No. 350,332, and the respective teachings thereof are incorporated herein by reference.
The available hand-operated vacuum pumps are effective in terms of operation. Also, these vacuum pumps are inexpensive since many of the components therein are molded plastic. However, a molded plastic construction is not especially durable and may break or become inoperative when used with various solvents or in a hostile environment. Thus, a need has arisen for a highly durable hand operated vacuum pump made at a reasonable cost.